Screw driver



J. J. KMET SCREW DRIVER Aug. 7, 1 934.

Filed Aug. 30, 1955 Patented Aug. 7, 1934 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to attachments for screw drivers and has for the primary object the provision of a device for tightly wedging the bit of a screw driver in the kerf of a screw to prevent slipping of the screw driver and the possibility of marring or injuring the walls of the kerf of the screw and is so mounted to the screw driver that it may be conveniently removed and replaced by another attachment of a different size so as to fit a kerf of a different size, thereby rendering a perfect connection between the screw driver and screws of different sizes or having kerfs of different sizes.

With these and other objects in View this invention consists in certain novel features of construction, combination and arrangement of parts to be hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawing, in which Figure l is a side elevation illustrating a screw driver with an attachment applied thereto and constructed in accordance with my invention.

Figure 2 is an edge elevation illustrating the attachment inserted in the kerf of a screw prior to moving the bit of the screw driver in the kerf.

Figure 3 is a fragmentary sectional view illustrating a means of retaining the attachment to the screw driver and showing the attachment in the kerf of a screw prior to the insertion of the bit of the screw driver into the kerf.

Figure 4 is a view similar to Figure 3 showing the attachment positioned in the kerf of the screw and wedged against the walls thereof by the bit of the screw driver entering the kerf.

Figure 5 is a fragmentary plan view showing the bit of the screw driver.

Figure 6 is a perspective view illustrating the attachment.

Referring in detail to the drawing, the numeral 1 indicates the handle of a screw driver carrying a shank 2 terminating in a bit 3. The bit tapers towards its free end and has oppositely arranged sloping faces over which is positioned the attachment 4. The shank 2 adjacent the bit 3 is provided with an opening 5 communicative with recesses 6 in opposite faces of the shank. One wall of the opening forms abrupt shoulders 7 to be engaged by the attachment 4 and lying in close proximity to the recesses 6.

The attachment 4 consists of side plates 8 connected, as shown at 9. The side plates are reduced to provide resilient gripping portions 10 having formed upon their opposing faces lugs 11 adapted to ride in the recesses 6 and engage the shoulders '7 during the use of the attachment on the screw driver. The plates 8 converge, as shown in Figure 6, and contact with each other. The attachment is applied to the screw driver, as shown in Figure 3, with the lugs 11 engaging the abrupt shoulders 7 and with the contacting ends of the plates 8 arranged beyond the end of the bit 3 so as to enter the kerf 12 of the screw prior to the bit. After the positioning of the plates 8 in the kerf 12, the screw driver is forced towards the screw bringing the bit in the kerf and spreading the plates against opposite walls of the kerf, thereby effectively wedging the bit in the kerf obviating possibility of the bit slipping from the kerf during the turning of the screw by the screw driver in either direction. When the bit forces the plates 8 apart the lugs 11 ride against the walls of the recesses 6 away from the shoulders '7. The lugs engaging the shoulders 7 prevent accidental removal of the attachment from the bit of the screw driver. However, when it is desired to change the attachment for another of a different size the flexible portions 10 are spread moving the lugs out of the path of the shoulders so that the attachment may be pulled off of the bit in an endwise direction.

While I have shown and described the preferred embodiment of my invention, it will be understood that minor changes in construction, combination and arrangement of parts may be made without departing from the spirit and scope of my invention, as claimed.

Having described the invention, I claim:

In combination with a screw driver bit provided with oppositely arranged tapered faces and an opening extending through said faces and forming a shoulder to each face, anda sloping Wall opposite to said shoulder, plates slidably engaging the faces, members connecting said plates with the latter projecting beyond the ends of said members to provide pairs of resilient portions, and tapering lugs formed on a pair of said resilient portions to ride against the sloping walls and r to engage with the shoulders.

JOHN J. KMET. 

